1. Field of the Invention
The invention relates to the field of data processing. More particularly, the invention relates to a method of optimizing application code for delivery to a client over a data connection, in which only those parts of the application code needed by a particular object within the application are delivered to the client with the object, thus minimizing download time.
2. Description of Related Art
In the world of web applications, developers face severe limitations when trying to deploy client-side functionality. In general, good development practice pushes developers toward the creation of a rich base of generalized code to draw from. This code base frequently becomes very diverse in the functionality it supports and very complicated in the dependencies, as more and more code is written that depends on the code that existed prior to it. This generalized code base is extremely powerful as it allows the rapid development of applications. And, in the traditional world of desktop applications, where memory and bandwidth are secondary constraints, deploying such a rich and weighty system has been moderately straightforward.
Web applications, on the other hand, are strictly limited in the amount of code that can be delivered to the client. A web application is little more than a set of web pages that support different functionalities. For example, a web presentation application may have one page for each of the following functions:                viewing the users' presentations;        editing a presentation; and        viewing a presentation.        
Thus, there is a dramatic limitation when it comes to delivering the client side functionality. A traditional desktop application may take 30 Mbytes of code to run—a conservative estimate. On a 56K modem line, this much information takes at least ten minutes to transfer to the client. It is unreasonable to expect the typical web user to wait this long for a page to load.
This leads to the problem addressed by this invention—that of deploying code to the client in an efficient and optimized manner.
The prior art provides various strategies and systems for optimizing application code in the web environment. For example, B. Muschett, W. Tracey, S. Woodward, Method and system in a computer network for bundling and launching hypertext files and associated subroutines within archive files, U.S. Pat. No. 6,026,437 (Feb. 15, 2000) describe a method and system in a computer network in which a HTML file having tags that point to particular applets is bundled into an archive file with the applets and the data associated with the applets. In response to a client request to download the hypertext file; the file, the applets, and associated data are downloaded as a single archive file. While the described invention reduces download time by increasing data packaging efficiency and eliminating the need for multiple data requests to the server for multiple objects; the single object created, incorporating the hypertext page, the applet or applets and the associated data, results in a large data object, which itself, requires substantial download time. Furthermore, the described system makes no attempt to reduce the amount of data downloaded; it merely packages and transmits it more efficiently. Moreover, since the hypertext file and the applet are packaged together in the same archive file, both applet and hypertext file must be downloaded every time the client requests the hypertext file.
C. Bryant, T. Goin, T. Moos, D. Steele, Apparatus and method for increasing the performance of interpreted programs running on a server, U.S. Pat. No. 6,141,793 (Oct. 1, 2000) describe an apparatus and method in which interpreted scripts, such as CGI scripts are consolidated into a single process, similar to a library of interpreted code routines. When the process is to be executed, the interpreted process forks its self and has the resulting child process run the already compiled interpreted code. In this way, the interpreted code need only be compiled once, rather than compiling over and over again. While the described invention improves the performance of the interpreted program by eliminating redundant processing steps, it is not concerned with optimizing the interpreted code, or providing only those code sections that are necessary for the task at hand. Furthermore, the described invention is concerned only with server side programs, it has nothing to do with interpreted programs and scripts run on the client side, and it is unconcerned with minimizing download time by reducing the amount of code to be downloaded to and interpreted on the client.
There exists, therefore a need in the art for a method of deploying application code to a client in an efficient and optimized manner. It would be highly desirable to reduce the amount of data to be downloaded by optimizing code in such a way that only that code needed by a particular object, for example a web page, is supplied to the client with the object, so that download time is minimized. Furthermore, it would be desirable to cache the application code on the client, so that the optimized code need only be downloaded once, instead of every time the object is requested from the server.